Facebook’s Sheryl Sandberg has explained why the company made the controversial decision to pay for its female employees to freeze their eggs in an interview in which she called on more companies to offer family-friendly perks. “Right now work does not work for parents,” she said.

“There is a young woman working at Facebook who had got cancer,” Sandberg told Bloomberg. “I knew her and she came to me and said I’m going to get treatment and that means I wont be able to have children unless I can freeze my eggs and I can’t afford it but our medical care doesn’t cover it.”

Sandberg said she went to ask Facebook’s head of human resources and said the company should pay for the employee’s egg freezing. “We stopped and looked at each other and said why would we only cover this for women with cancer why wouldn’t we cover this more broadly and that was where that benefit came from, and we think it’s great.”

Both Facebook and Apple, which also began offering the egg freezing perk in January, have were criticised for the policy that some thought encouraged women to put their careers ahead of starting a family.

Sandberg said the policy was part of Facebook’s wider benefits package to allow working families more flexibility, including four months paternity and maternity leave whether parents adopt or have children and a lump sum baby gift.

She said companies need to more to help both mothers and fathers. “The ‘have it all language’ is only applied to women. Having it all means to have children and have work, we assume men can have both and they do.

“The problem is we assume women can’t but women do, and have to – 70% of mothers in the United States are in the workforce because they have to be, so telling women constantly ,you can’t have it all, you can’t have it all’ is not helpful because they have to be parents and work,” she said. “It turns out fathers have to work and be parents too. Right now, work does not work for parents, both men and women get discouraged from leaving [the office]. Men [worry they’re] not going to be seen as serious if they go home to be with a child.”

Sir Richard Branson, the Virgin founder, who was interviewed alongside Sandberg, said he couldn’t understand why Facebook was criticised for the egg freezing policy and said he hoped to introduce at Virgin.

“How can anybody criticise them for doing that … It’s the woman’s choice. If they want to carry on working, they can carry on working,” Branson said. “If they haven’t managed to find the man of their dreams by 35,36,37, 38 freeze the eggs – it makes sense the earlier you can freeze them the better.

“We at Virgin want to steal the idea and give it to our women.”

Branson, 64, claimed he had spent as much time with his children growing up as his wife, and that he changed nappies during business meetings. “When my kids were young I moved out of the office, [and] I worked from home. I had the kids crawling around while I was having meetings. I would be changing nappies whilst we were having meetings. Companies should give men that flexibility to work from home to be able to spend time at home.”